On Mon, Jul 11, 2016 at 11:51 AM, David Majnemer <david.majne...@gmail.com> wrote:
> > > On Mon, Jul 11, 2016 at 8:42 AM, Nico Weber <tha...@chromium.org> wrote: > >> On Mon, Jul 11, 2016 at 11:36 AM, David Majnemer < >> david.majne...@gmail.com> wrote: >> >>> >>> >>> On Mon, Jul 11, 2016 at 7:18 AM, Nico Weber <tha...@chromium.org> wrote: >>> >>>> VS2013's cl.exe doesn't understand /Zd, 2015's doesn't either. This >>>> means people who want to ask clang-cl for line tables only will have to add >>>> this flag in some if(is_clang) block in their build file anyways. What's >>>> the advantage of giving this flag a spelling that's different from both cl >>>> and clang? With -gline-tables-only, an if(is_clang) works on Linux, Mac, >>>> Windows. >>>> >>>> (Even if there's a good case for /Zd, I don't think we should remove >>>> user-exposed flags without a strong reason, so even if we keep /Zd I think >>>> we should also keep exposing -gline-tables-only.) >>>> >>> >>> Existing users of -gline-tables-only? I'd imagine any responsible users >>> of -gline-tables-only would probably use their build system to verify that >>> the flag exists. We have never released an official LLVM which supported >>> it (LLVM 3.8 came out in early March and -gline-tables-only was exposed via >>> clang-cl in mid March). >>> >> >> Ok, but why is /Zd better than -gline-tables-only? >> > > I see a few reasons: > - It is less surprising for a debug flag in the cl world to be called > /Zsomething instead of -gsomething. > Eh, you'll have to look it up either way to find the flag. And when seeing the flag, the -g flag is more self-explanatory. Also, it is surprising that a clang-cl /-style flag doesn't work with cl, so it just moves the surprise around a bit. > - I think that avoiding invasion of their namespace, when possible, is a > good thing. It makes it less likely that we will conflict with a flag they > want to add in the future. > I don't understand this point. Doesn't invading their namespace make collisions _more_ likely? > - I imagine that if they wanted to add support back for > -gline-tables-only, they'd name it /Zd. > Given they had this flag and removed it, they probably didn't like it very much :-) > I'm sympathetic to the argument that "-gline-tables-only" is more familiar > to Linux/Mac OS X folks and that /Zd won't work across all platforms. > > Here why I think that's ok: > - This is not really a new problem. If you want to select c++1z you get > to spell it /std:c++latest for clang-cl and -std=c++14. > Sure, but these are flags that clang/gcc and cl interpret. So if you have a gcc build and a visual studio build, it's fairly easy to get each going with clang / clang-cl. With /Zd, we're needlessly inventing a new spelling for an existing clang flag. As far as I can see, the new name creates a (small) problem without solving one. So far, when we wanted to add a flag that cl doesn't have and that clang has, we've always gone for the clang spelling of that flag. That seems like a good guideline to me. > - People who want harmony between Mac OS X, Linux and Windows on the > driver side can just use clang++. > > >> >> >>> >>> I'd consider it in poor form for users to take a hard dependency on a >>> flag which only exists in a compiler which has never been released. >>> >>> I'd agree with you if -gline-tables-only had made its way to an actual >>> release. >>> >>> >>>> >>>> On Mon, Jul 11, 2016 at 10:08 AM, Nico Weber <tha...@chromium.org> >>>> wrote: >>>> >>>>> This breaks existing users of -gline-tables-only. What's the >>>>> motivation for this change? >>>>> >>>> >>>>> On Sat, Jul 9, 2016 at 5:49 PM, David Majnemer via cfe-commits < >>>>> cfe-commits@lists.llvm.org> wrote: >>>>> >>>>>> Author: majnemer >>>>>> Date: Sat Jul 9 16:49:16 2016 >>>>>> New Revision: 274991 >>>>>> >>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=274991&view=rev >>>>>> Log: >>>>>> [clang-cl] Add support for /Zd >>>>>> >>>>>> MASM (ML.exe and ML64.exe) and older versions of MSVC (CL.exe) >>>>>> support a >>>>>> flag called /Zd which is more-or-less -gline-tables-only. >>>>>> >>>>>> It seems nicer to support this flag instead of exposing >>>>>> -gline-tables-only. >>>>>> >>>>>> Modified: >>>>>> cfe/trunk/include/clang/Driver/CLCompatOptions.td >>>>>> cfe/trunk/include/clang/Driver/Options.td >>>>>> cfe/trunk/lib/Driver/Tools.cpp >>>>>> cfe/trunk/test/Driver/cl-options.c >>>>>> >>>>>> Modified: cfe/trunk/include/clang/Driver/CLCompatOptions.td >>>>>> URL: >>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/CLCompatOptions.td?rev=274991&r1=274990&r2=274991&view=diff >>>>>> >>>>>> ============================================================================== >>>>>> --- cfe/trunk/include/clang/Driver/CLCompatOptions.td (original) >>>>>> +++ cfe/trunk/include/clang/Driver/CLCompatOptions.td Sat Jul 9 >>>>>> 16:49:16 2016 >>>>>> @@ -166,6 +166,8 @@ def _SLASH_Zc_trigraphs_off : CLFlag<"Zc >>>>>> HelpText<"Disable trigraphs (default)">, Alias<fno_trigraphs>; >>>>>> def _SLASH_Z7 : CLFlag<"Z7">, >>>>>> HelpText<"Enable CodeView debug information in object files">; >>>>>> +def _SLASH_Zd : CLFlag<"Zd">, >>>>>> + HelpText<"Emit debug line number tables only">; >>>>>> def _SLASH_Zi : CLFlag<"Zi">, Alias<_SLASH_Z7>, >>>>>> HelpText<"Alias for /Z7. Does not produce PDBs.">; >>>>>> def _SLASH_Zp : CLJoined<"Zp">, >>>>>> >>>>>> Modified: cfe/trunk/include/clang/Driver/Options.td >>>>>> URL: >>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=274991&r1=274990&r2=274991&view=diff >>>>>> >>>>>> ============================================================================== >>>>>> --- cfe/trunk/include/clang/Driver/Options.td (original) >>>>>> +++ cfe/trunk/include/clang/Driver/Options.td Sat Jul 9 16:49:16 2016 >>>>>> @@ -1229,7 +1229,7 @@ def fdebug_prefix_map_EQ >>>>>> def g_Flag : Flag<["-"], "g">, Group<g_Group>, >>>>>> HelpText<"Generate source-level debug information">; >>>>>> def gline_tables_only : Flag<["-"], "gline-tables-only">, >>>>>> Group<gN_Group>, >>>>>> - Flags<[CoreOption]>, HelpText<"Emit debug line number tables >>>>>> only">; >>>>>> + HelpText<"Emit debug line number tables only">; >>>>>> def gmlt : Flag<["-"], "gmlt">, Alias<gline_tables_only>; >>>>>> def g0 : Flag<["-"], "g0">, Group<gN_Group>; >>>>>> def g1 : Flag<["-"], "g1">, Group<gN_Group>, >>>>>> Alias<gline_tables_only>; >>>>>> >>>>>> Modified: cfe/trunk/lib/Driver/Tools.cpp >>>>>> URL: >>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=274991&r1=274990&r2=274991&view=diff >>>>>> >>>>>> ============================================================================== >>>>>> --- cfe/trunk/lib/Driver/Tools.cpp (original) >>>>>> +++ cfe/trunk/lib/Driver/Tools.cpp Sat Jul 9 16:49:16 2016 >>>>>> @@ -6269,12 +6269,18 @@ void Clang::AddClangCLArgs(const ArgList >>>>>> >>>>>> CmdArgs.push_back(Args.MakeArgString(Twine(LangOptions::SSPStrong))); >>>>>> } >>>>>> >>>>>> - // Emit CodeView if -Z7 is present. >>>>>> - *EmitCodeView = Args.hasArg(options::OPT__SLASH_Z7); >>>>>> - if (*EmitCodeView) >>>>>> - *DebugInfoKind = codegenoptions::LimitedDebugInfo; >>>>>> - if (*EmitCodeView) >>>>>> + // Emit CodeView if -Z7 or -Zd are present. >>>>>> + if (Arg *DebugInfoArg = >>>>>> + Args.getLastArg(options::OPT__SLASH_Z7, >>>>>> options::OPT__SLASH_Zd)) { >>>>>> + *EmitCodeView = true; >>>>>> + if (DebugInfoArg->getOption().matches(options::OPT__SLASH_Z7)) >>>>>> + *DebugInfoKind = codegenoptions::LimitedDebugInfo; >>>>>> + else >>>>>> + *DebugInfoKind = codegenoptions::DebugLineTablesOnly; >>>>>> CmdArgs.push_back("-gcodeview"); >>>>>> + } else { >>>>>> + *EmitCodeView = false; >>>>>> + } >>>>>> >>>>>> const Driver &D = getToolChain().getDriver(); >>>>>> EHFlags EH = parseClangCLEHFlags(D, Args); >>>>>> @@ -9964,7 +9970,8 @@ void visualstudio::Linker::ConstructJob( >>>>>> >>>>>> CmdArgs.push_back("-nologo"); >>>>>> >>>>>> - if (Args.hasArg(options::OPT_g_Group, options::OPT__SLASH_Z7)) >>>>>> + if (Args.hasArg(options::OPT_g_Group, options::OPT__SLASH_Z7, >>>>>> + options::OPT__SLASH_Zd)) >>>>>> CmdArgs.push_back("-debug"); >>>>>> >>>>>> bool DLL = Args.hasArg(options::OPT__SLASH_LD, >>>>>> options::OPT__SLASH_LDd, >>>>>> >>>>>> Modified: cfe/trunk/test/Driver/cl-options.c >>>>>> URL: >>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/cl-options.c?rev=274991&r1=274990&r2=274991&view=diff >>>>>> >>>>>> ============================================================================== >>>>>> --- cfe/trunk/test/Driver/cl-options.c (original) >>>>>> +++ cfe/trunk/test/Driver/cl-options.c Sat Jul 9 16:49:16 2016 >>>>>> @@ -420,7 +420,7 @@ >>>>>> // Z7: "-gcodeview" >>>>>> // Z7: "-debug-info-kind=limited" >>>>>> >>>>>> -// RUN: %clang_cl -gline-tables-only /Z7 /c -### -- %s 2>&1 | >>>>>> FileCheck -check-prefix=Z7GMLT %s >>>>>> +// RUN: %clang_cl /Zd /c -### -- %s 2>&1 | FileCheck >>>>>> -check-prefix=Z7GMLT %s >>>>>> // Z7GMLT: "-gcodeview" >>>>>> // Z7GMLT: "-debug-info-kind=line-tables-only" >>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> cfe-commits mailing list >>>>>> cfe-commits@lists.llvm.org >>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >>>>>> >>>>> >>>>> >>>> >>> >> >
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